Conventional resurfacing machines of the type that resurfaces guide plugs used in the sawmill industry have a pair of opposed upper and lower turntables. The turntables each have a replaceable cutting tool which includes a diamond stylus or the like. A workpiece is fed into the space between the rotary turntables and is resurfaced by the scraping action of the cutting tools. An example of this type of machine is shown in the Emter U. S. Pat. No 4,685,845 entitled GUIDE PAD RESURFACING APPARATUS. In this patent, each turntable includes a slot which receives a rectangular cutting tool containing a diamond stylus. The tool is held in the slot by a screw, and cutting depth is regulated by an adjustment screw bearing against the tool from the other side of each turntable. The adjustment screw torsions the tool slightly causing It to bend to achieve proper depth. A tool of this type can be found In U.S. Pat. No. 6,319,104.
Resurfacing machines of this type use a pair of turntables to resurface the pads on opposite sides of a single saw guide. In conventional sawmill operations however, there are guide pads on either side of a saw blade. This calls for two saw guides. The guide pads must be milled to strict tolerances and It is Important that the guide pad surfaces on either side of the saw blade be parallel to one another. It is very difficult, however, in a resurfacing operation in which guide pads are resurfaced one at a time to insure that any two guide pads on different saw guides will have perfectly parallel surfaces. Small differences in set-up and alignment of individual guide pads can change the angle at which the resurfacing operation takes place. While the intent Is that the guide pads be perfectly horizontal relative to the turntables and cutting apparatus, in practice this is not always the case, because there are several sources of error that can affect alignment, and hence parallelism, of the guide pads.
One major source of Inaccuracy is the sliding support block to which the guide pads are affixed. This block Is attached to a motor that causes it to slide reciprocally along a frame so that it moves the guide pad into and out of engagement with the cutting tools located on the spinning turntables. The guide pad is usually connected to a holder by a bolt or the like, which holds it in the horizontal plane. Small differences In the attachment of individual saw guides can mean that one saw guide may be resurfaced at an angle that Is slightly different from the next or previous one.
The resurfacing process is accomplished by tools having diamond-tipped heads which are affixed to the upper and lower turntables. The turntables rotate causing a series of arcs to be cut Into the surfaces of the pads. A conventional support block slides on runners which are long rails arranged on the frame. The block includes cutout portions on its underside which are slots milled to fits the rails. Thus, the weight of the support block bears directly against the two raised rails bolted to the frame.
Both the rails and the slots must be machined to very close tolerances. The rails have to be precisely aligned and must undergo a regrinding operation after manufacture. Further, they have to be heat-treated for hardening to keep wear to a minimum and to reduce xe2x80x9cgalling.xe2x80x9d Galling is the tendency of metal filings to smear into the surface over time and create small ridges or bumps. Further, when the machines are shipped, any shock or jarring can cause the rails to become misaligned. Any misalignment can cause the guide pads to be resurfaced unevenly.
An apparatus for resurfacing a pair of guide plugs on different saw guides includes a turntable rotatably mounted on a frame having cutting tools interacting with resurfaceable guide plugs mounted on a reciprocating slide assembly which includes a guide support block adapted for reciprocating motion with respect to the cutting tools. The block has a pair of oppositely disposed saw guides selectively attached thereto so as to be parallel to each other so that parallelism is maintained during the resurfacing process.